Evaporation characteristics of metallic materials for vacuum electron devices

Evaporation properties of Monel and stainless-steel alloy materials that are widely applied in microwave vacuum electron devices have been studied by time-of-flight mass spectrometry (ToFMS) as their evaporants has an immediate impact on lifetime reliability. The composition sizes stainless steel determined. Minor evaporation Mn, Cu, Cr occurred at ∼800°C, which is much lower than the melting points Cr, increased with increasing temperature. Experimental results show ToFMS a very fast testing method for researching metallic material evaporation. At 900°C, substantial changes surface microstructures high porosity many grain boundaries were observed. With treatment time, gradually became larger, decreasing strength leading to outgassing or even air leakage. Such phenomena analyzed based relevant theory, appropriate feasible methods use discussed from perspective device design process control.